The ever-increasing demands on RF and microwave circuitry design and development teams to achieve EMC, eliminate crosstalk, save PCB real estate, decrease overall product size, provide access for rework and, last but not least, reduce production costs, has led to the development of labyrinth and lid shielding assemblies.To get more news about Cavity PCB, you can visit pcbmake official website.
Alternatives to the labyrinth and lid approach are either a multitude of individual shielding cans or a labyrinth milled from a solid material, generally aluminium.
The disadvantages of multiple cans, even if they can be machine-placed from tape and reel, are a considerable increase in the PCB real estate because of double tracks for the individual cans and the space required between the cans for adjacent spring finger or other lid fixings.
If the labyrinth is machined from solid material, then, inevitably, the walls will be thicker than the photo-chemical machined labyrinth, and the connection to the PCB may not be as effective as a seam-soldered joint.
A labyrinth is hand-placed onto the PCB as a one-piece assembly between the electronic component pick-and-place operation and the re-flow soldering; hence, a seam-soldered joint can be achieved around any cavity that requires shielding.
The lid can be fitted following additional production processes, such as visual inspection, in-circuit testing, and in any subsequent rework of the PCB.One method of producing screening enclosures is photo-chemical machining (PCM), a method that offers many advantages to both the development engineer and those involved in volume manufacturing.
The PCM process uses relatively inexpensive photo-tooling created from either manual drawings or CAD information provided by the customer. The process allows changes to be made rapidly and without the considerable expense and lead times required with hard tooling.
The design process includes the basic outline and fold lines for forming (both of which can be complex shapes) and location tags, all of which can be manufactured without the need for special tools. The mechanical designer can be as creative as he wishes regarding track clearance apertures and connector or other lead-through component holes since these complexities are contained within the photo-tooling and do not directly affect the individual component cost.
